Crane boom mounting



Dec. 5, 1950 w. s. BURDICK ET AL CRANE BOOM MOUNTING 2 Sheets-Sheet 1 Filed Feb. 9, 1948 Mgr/8010m- Dec. 5, 1950- w. s. BURDICK El AL CRANE BOOM MOUNTING Filed Feb. 9, 1948 2 Sheets-Sheet 2 Elf/f E N W for cranes, power shovels and excavators.

Patented Dec. 5, 1950 CRANE BOOM MOUNTING Will S. Burdick, Wauwatosa, and Karl Schneider,

Greendale Village, Wis, assignors to Harnischfeger Corporation, Milwaukee, Wis, a corporation of Wisconsin Application February 9, 1948, Serial No. 7,207

Claims.

This invention relates to boom constructions More specificall it resides in an improved mounting construction by which the base of the boom is attached to the rotating frame which houses instrumentalities for actuating the boom and in which main central thrust withstanding working boom feet disposed near the center line of the boom, which engage and are carried by boom foot sockets attached to the frame, are arranged to act in conjunction with widely spread preferably non-engaging supplementary mountings capable of withstanding both compression and tension forces met only under extreme conditions of working.

Among the objects of this invention is to provide increased lengths of moment arm for withstanding abnormal sidewise loading of the boom thus minimizing stresses resulting from such loading, and to provide such increased lengths of moment arm without precluding that limited rolling and flexibility of the boom which is beneficial in the absorbing of shocks.

The above and other objects and advantages of this invention will appear in the description which follows. In the description reference is made to the accompanying drawings which form a part hereof, in which there is set forth by way of illustration and not of limitation one form in which the apparatus of this invention may be embodied.

In the drawings:

Fig. 1 is a side view in elevation of a power shovel provided with a boom mounting constructed in accordance with this invention;

Fig. 2 is a fragmentary detail plan view, viewed as indicated at 2-2 in Pg. 1, of the base of the boom and the mounting therefor, shown in Fig. 1;

Fig. 3 is a fragmentary detail side view in elevaton viewed as indicated at 33 in Fig. 2 of the base of the boom. and the mounting therefor, shown in Fig. 1;

Fig. 4 is a fragmentary enlarged detail plan view with parts broken away and in section of one of the supplemental mountings between the boom and rotatable frame of the apparatus shown in Fig. 1, and

Fig. 5 is a fragmentary enlarged detail side view in elevation with parts broken away and in section of one of the supplemental mountings between the boom and the rotatable frame of the apparatus shown in Fig. 1.

Referring now to the drawings, there is shown in Fig. 1 a power shovel having a car body i with l track type treads upon which is mounted a rotatable cab 2 containing motivating apparatus and controls. Mounted on the cab 2 is a boom 3 which supports a shiftable dipper handle 4 which carries a dipper 5. Suspension for the boom 3 is provided in the form of cables extending to the gantry frame 6, as shown. As appears more clearly in Figs. 2 and 3 the base of the boom 3 is provided with boom feet I which rest and pivot in boom foot sockets 8 attached to the frame 9 of the cab 2.

Under ordinary working conditions of digging and hoisting the stresses developed in the boom result in a more or less simple thrust which is transmitted through the boom feet l and withstood entirely by the boom foot sockets 8. When the cab is rotated, however, substantial sidewise loads are imposed by the inertia of the boom, dipper handle, dipper and load Within the dipper. Such sidewise loads result in stresses other than simple thrust at the boom foot sockets 8. In addition to such inertia induced stresses the digging operation itself may give rise to forces which result in stresses other than simple thrust at the boom foot sockets 8. Since the boom foot sockets B are ill-adapted to withstand loading other than simple thrust, supplementary means to withstand loads other than simple thrust are provided, such means being adapted to permit limited yielding to minimize the intensity of peak stresses.

Boom 3 as shown is constructed in the form of a box member made up of side plates 32 to which are welded cover plate 33 and a corresponding bottom plate not shown. At the lower end of the boom 3. the box section is spread laterally by gusset channels 42 to form a boom base which extends well beyond the boom feet '1 on both sides of the boom 3. A reinforcing top plate I is secured to the cover plate 33 and gussets 42 and a reinforcing lower plate 34 is secured to the bottom plate and bent upwardly at the lower end of the boom as appears more clearly in Fig. 3. Internal bracing not shown extends transversely across the lower end of the base of the boom between the reinforcing plates ii) and 34, the same terminating in abutments [2 which extend beyond the sides of the base of the boom. The abutments l 2 are strengthened by additional internal transverse bracing also not shown which terminates in the lugs l3 disposed a short distance from the abutments l2 and secured thereto by means of spacer blocks M which are welded in position as shown.

Und r normal loading of the boom 3, abutments I 2 engage no part connected with the frame 9 of the cab 2 and impose no load thereon. However, hinged seat brackets ll, pivotally at tached to the frame 9 of the cab 2, by means of lugs i and it and hinge pins 24, present faces 35 in position to receive thrusts applied by abut ments it. whenever sidewise loading of the boom exceeds a predetermined amount. As appears more clearly in Figs. 4 and 5 each hinged bracket l? is made up of an engagement face portion 35 to which there is secured hinge ears 3! and 2!. Hinge pins 2e are held securely in place by meansof end washers 25 and through bolts 33 as shown.

Also forming a part of each hinged bracket assembly H is a U-bolt 2S dimensioned to closely surround the ear ii at its lower end being welded thereto as shown. Each U-bolt 29 extends forwardly from its bracket ll through notches formed in the corresponding engagement face portion 36, abutment l2 and block l4, and thence through holes-provided in the corresponding lug !3 to a position substantially beyond the same as shown. Surrounding the ends of the U-bolts 2Q beyond the lugs l3 are compression springs held in place by compression plates 28 and nuts 21. The nuts. 2'! are held in place by sheet metal clip plates 29 as shown.

Since it is difficult in constructing apparatus of the type here involved economically to achieve the dimensional accuracy required toensure a predetermined spacing between the abutments l2 and the engagement faces 35 of the hinge brackets II, it is preferredthat the apparatus be so constructed to provide very substantial clearances between these parts which may be largely occupied by abutment shims E8, the thickness of which may be selected after assembly is substantially complete. To facilitate insertion of the shims l3 and their retention, lower retaining flanges ll extending laterally from the base of the boom are provided. The flanges i i are provided with slots 39 indicated in dotted lines in Fig. 4 and in section in Fig. 5. After insertion of the shims i8 retaining plates l9 are welded in place as shown.

In order to permit minor torsional displacements of the boom 3 as well as minor sidewise displacements, the notches in abutments i2 and blocks Id which accommodate the U-bolts 28 and the holes through the lugs it are of such dimension as to provide a very substantial cle .rance as appears in Figs. 4 and 5.

In operation the boom 3 may be raised or lowered or retained in any position desired and in doing so the hinged brackets ll move to properly present their engagement faces 35 to the shims i8. When sidewise loading is imposed upon the boom 3 due either to swinging motions of the apparatus or to digging loads, a slight, lateral tilting motion of the boom occurs whereupon an abutment i2 applies a reaction to its corresponding hinge bracket H on one side of the boom in the form of a thrust or compression load while the springs 26 on the opposite side of the boom impart a tension load through the corresponding U-bolt 2i] to the corresponding hinge bracket. lhe sidewise loading of the boom is thus resisted by a couple acting on a widely spread lever arm equivalent substantially to the entire width of the frame 9 of the cab 2. This resisting couple is supplemented by the reaction of that boom foot 1' against its corresponding socket 8 which is adjacent that hinged bracket which is acting in compression. This action is in contrast to that which occurs where a. boom is restrained against sidewise loading by means of shrouds or so-callcd sway braces attached to the frame of the cab 2 and capable of acting only in tension. In the latter case the only compressive force available to set up. the necessary restraining couple must be provided through a reaction between the boom feet and the boom sockets. We have found that peak stresses occurring in our improved apparatus are very substantially smaller than the peak stresses occurring in the older form of apparatus above referred to for equivalent loads.

In providing supplementary load resisting means capable of acting both in tension and in compression it is necessary as heretofore pointed out to provide for limited yicldability and by reason of the same it is advisable that provision be made for prevention of extreme displacements f the parts. For this purpose the top reinforcing plate it! is extended as shown at 3% to provide ears disposed directly above corresponding ears 4| formed as a part of the lower retaining flanges i l. Arranged to pass loosely through holes in. the ears 4% and ii are stop pins 39 held in place by retaining pins 3i which engage lugs 22 and 23 securely welded to ears 3'! of hinged brackets 17. By reason of the clearance between the stop pins 313 and the ears 48 and M they come into action only in case of extreme overloading or in case of failure of some part which permits abnormal displacement of the boom 3.

We claim:

1. In a crane having a frame and a boom, a mounting for said boom comprising a transversely extending base secured to and forming a part of the inner end of said boom, inwardly facing medially disposed main thrust transmitting means secured to said transversely extending base, main thrust receiving means secured to said frame adapted to be engaged by and to hold said main thrust transmitting means, a supplementary thrust transmitting abutment member secured to said boom base'on one side thereof at a point laterally spaced from said. main thrust transmitting means, a supplementary thrust receiving Inez-.- ber secured to said frame in position to receive thrust transmitted by said supplementary thrust transmitting abutment upon transverse loading of said boom, tension resisting means anchored at one end to said boom in substantial alignment with said supplementary thrust transmitting abutment member and at its opposite end to said frame near said supplementary thrust receiving member, a second supplementary thrust trans mitting abutment member secured to the opposite side of said boom base, a second supplementary thrust receiving member secured to said frame to receive thrust transmitted by said second supplementary thrust transmitting abutment member upon transverse loading of said boom, and a second tension resisting means anchored at one end to said boom in substantial alignment with said second supplementary thrust transmitting abutment member and at its opposite end to said frame near said second supplementary thrust receiving member.

2. In a crane having a frame and a boom, a mounting for said boom comprising a transversely extending base secured to and forming a part of the inner end of said boom, inwardly facing medially disposed main thrust transmitting means secured to said transversely extending base, main thrust receiving means secured to said frame adapted to be engaged by and to hold said main thrust transmitting means, a supplementary thrust transmitting abutment member secured to said boom base on-one side thereof at a point laterally spaced from said main thrust transmitting means, a supplementary'thrust receiving member secured to said frame in spaced re1ationship to said supplementary thrust transmitting abutment adapted upontilting of the boom toward the same to receive thrust transmitted by said supplementary thrust transmitting abutment, tension resisting means secured to and adapted to resist and limit separation of said supplementary thrust transmitting abutment and said supplementary thrust receiving member, a second supplementary thrust transmitting abutment member secured to the opposite side of said boom base, a second supplementary thrust receiving member secured to said frame in spaced relationship to said second supplementary thrust transmitting abutment member adapted to receive thrust transmitted by said second supplementary thrust transmitting abutment member upon tilting of the boom toward the same, and tension resisting means secured to and adapted to resist and limit separation of said second supplementary thrust transmitting abutment member and said second suppl mentary thrust receiving member.

3. In a crane having a frame and a pivoted boom, a mounting for said boom comprising a transversely extending base secured to and forming a part of the inner end of said boom, main thrust transmitting means secured to said boom base, main thrust receiving means mounted on said frame pivotally engaging said main thrust transmitting means, a supplementary thrust transmitting abutment member secured to said boom base on one side thereof at a point laterally spaced from said main thrust transmitting means, a pivotally mounted supplementary thrust receiving member secured to said frame, means engaging said boom and said supplementary thrust receiving member adapted to maintain said supplementary thrust receiving member in thrust resisting alignment with said boom in all pivotal positions of said boom, tension resisting means anchored at one end to said boom in substantial alignment with said supplementary thrust transmitting abutment and at its opposite end to said supplementary thrust receiving member, a second supplementary thrust transmitting abutment member secured to the opposite side of said boom base, a second pivotally mounted supplementary thrust receiving member secured to said frame, means engaging said boom and said second supplementary thrust receiving member adapted to maintain said second supplementary thrust receiving member in thrust resisting alignment with said boom in all pivotal positions of said boom, and tension resisting means anchored at one end to said boom in substantial alignment with said second supplementary thrust transmitting abutment and at its opposite end to said second supplementary thrust receiving member.

4. In a crane having. a frame and a boom, a mounting for said boom comprising a transverse- 1y extending base secured to and forming an integral part of the inner end of said boom, a pair of main thrust transmitting boom feet attached to and extending inwardly from said base and medially disposed in respect thereto, a pair of main thrust receiving boom foot sockets mounted on said frame engaging and supporting said boom feet for pivotal support of said boom, an inwardly facing supplementary thrust transmitting abutment member secured to one side of said boom base and laterally disposed in relation to said boom feet, a supplementary thrust receiving bracket member hingedly secured to said frame in spaced relation to said supplementary thrust transmitting abutment member adapted upon tilting of said boom toward the same to receive thrust transmitted by said supplementary thrust transmitting abutment member in all pivotal positions of said boom, spring means interposed between and adapted to resiliently oppose separation of said supplementary thrust transmitting abutment member and said supplementary thrust receiving bracket member, lost motion stop means interposed between said boom base and said supplementary thrust receiving bracket member adapted to limit separation thereof, a second inwardly facing supplementary thrust transmitting abutment member secured to the opposite side of said boom base in symmetrical relationship to said first inwardly facing supplementary thrust transmitting abutment member, a second supplementary thrust receiving bracket member hingedly secured to said frame in spaced relation to said second supplementary thrust transmitting abutment member adapted upon tilting of said boom toward the same to receive thrust transmitted by said second supplementary thrust transmitting abutment member in all pivotal positions of said boom, a second spring means interposed between and adapted to resiliently oppose separation of said second supplementary thrust transmitting abutment member and said second supplementary thrust receivingbracket member, and lost motion stop means interposed between said boom base and said second supplementary thrust receiving bracket member adapted to limit separation thereof.

5. In a boom mounting for cranes having a frame and a boom extending therefrom, the combination comprising boom feet secured to the inner end of said boom, boom foot sockets secured to said frame in engagement with and forming a support for said boom feet, supplementary brackets attached to said frame laterally disposed with respect to said boom foot sockets and presenting outwardly facing engagement faces, compressive abutments secured to said boom in aligned facing relationship with said engagement faces on said brackets, said compressive abutments being positioned on said boom so as to be spaced and normally to be held spaced from said engagement faces by engagement of said boom feet with said boom foot sockets, and extensible resilient means secured to said brackets and said abutments urging the same toward one another and acting to resiliently resist separation thereof.

WILL S. BURDICK. KARL SCHNEIDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,747,946 Mitchell et a1 Feb. 18, 1930 1,898,453 Lehman et a1. Feb. 21, 1983 2,426,587 Beckwith Sept. 2, 1947 

